A conventional LED tube lamp typically includes a lamp tube, a light bar configured with a plurality of LED light sources thereon, and an end cap configured on both ends of the lamp tube. The end cap has a power supply disposed therein, and the LED light sources and the power supply are electrically connected by the light bar. The conventional LED tube lamp possesses several common quality problems or issues such as the following: (1) The light bar is typically a rigid board or plate, thus upon breakage or rupture of the lamp tube (the lamp tube is typically made of glass, which is easy to break), such as partial breakage when broken into two parts, the entire lamp tube is still able to maintain a straight tube configuration, then the user may be under a false impression the LED tube lamp still remains usable and fully functional, and thus easy to cause electric shock or current leakage upon handling or installation thereof. (2) The rigid light bar is typically electrically connected to the end cap using metal conductive wires through wire bonding technique, which sometimes results in occasional or sporadic breakage of the metal conductive wires during manufacturing, transportation, and/or usage of the LED tube lamp, which then render the LED tube lamp unusable. (3) Conventional tube lamp configured with the plastic end caps requires a tedious process for performing adhesive bonding attachment and because the adhesive bonding process requires a significant amount of time to perform, production bottleneck or difficulties are resulted. In addition, manual operation or labor are required to perform such adhesive bonding process, thus would be difficult for manufacturing optimization using automation. The adhesive used are typically silicone adhesive or hot melt adhesive which are easily prone to overflow and spillover that are difficult to control or limit, and that the overflow or spillover of the hot melt adhesive requires removal by performing of manual adhesive wipe off or clean off so as to preserve aesthetic appearance of the LED tube lamp. (4) The conventional lamp tube is typically of a substantially uniformly round cylindrical structure, with the end cap fittingly sleeved on the outside of the lamp tube, and is adhesively bonded to the lamp tube. As a result, the outside diameter of the end cap is larger than the outside diameter of the lamp tube. During shipping or transport of the LED lamp tube, the shipping packaging support/bracket only makes direct contact with the end caps, thus rendering the end caps as being the only load/stress points, which can easily lead to breakage of the glass lamp tube. Referring to US patent publication no. 20100103673, which discloses of an end cap made of glass, with the end cap to be inserted into the glass lamp tube, thereby producing an exerting opposing force at both ends of the lamp tube from inside towards outside thereof, but from a outside towards the inside perspective of the glass lamp tube, the amount of accommodating force which can be tolerated by the glass lamp tube is reduced, thus causing easier breakage of the glass lamp tube at a same amount of force exertion from outside source. (5) The conventional LED tube lamp has the LED light sources spatially arranged and configured on the light bar, but because of the illumination and optical properties of each of the LED chips, grainy spots would be produced from illumination of the LED lamp tube when no further optical treatment or manipulation is additionally performed, thus negatively affect illumination quality. For example, a person can view the illuminating light directly coming from the LED light sources so as to produce the resulting visual graininess effect. To solve above problem, Chinese patent application CN201320748271.6 introduced a light diffuser tube and placed into a glass tube, in order to reduce the negative grainy visual effects. However, the presence of the light diffuser tube adds an additional interface medium to increase the overall light propagation path, which increases the probability of total reflection of light propagation thereby reducing light output efficiency. In addition, due to the light absorbing nature of the light diffuser tube, it will result in reduced light output efficiency.